Tool for tab terminal connector means



May 17, 1966 Original Filed Aug. 5, 1963 R. J. KINKAID ETAL TOOL FOR TABTERMINAL CONNECTOR MEANS 5 Sheets-Sheet 1 a8 QOBERTI (/Nm/a efa/ QPBERT,7,

y 1966 R. J. KINKAID ETAL 3,251,125

TOOL FOR TAB TERMINAL CONNECTOR MEANS Original Filed Aug. 5, 1963 5Sheets-Sheet 2 INVENTOE= QZL'J/Kw #444.

May 17, 1966 R. J. KINKAID ETAL TOOL FOR TAB TERMINAL CONNECTOR MEANS 5Sheets-Sheet 3 Original Filed Aug. 5, 1965 y 1966 R. J. KINKAID ETAL3,251,125

TOOL FOR TAB TERMINAL CONNECTOR MEANS Original Filed Aug. 5, 1963 5Sheets-Sheet 4 [1W5 N T02 P012527 7 (mm/0 H/ B RT H. 5411172.

May 17, 1966 R. J. KINKAID ETAL 3,251,125

TOOL FOR TAB TERMINAL CONNECTOR MEANS Original Filed Aug. 5, 1963 5Sheets-Sheet 5 I N VE IV TOE: 2 OBERT f/Nm/o f a/ R se/er H. Pn/wrzUnited States Patent TOOL FOR TAB TERMINAL CONNECTOR MEANS Robert J.Kinkaid, New Cumberland, and Robert H. Frantz, Mount Holly Springs, Pa.,assignors to AMP Incorporated, Harrisburg, Pa.

Original application Aug. 5, 1963, Ser. No. 299,866, now Patent No.3,173,737, dated Mar. 16, 1965. Divided and this application Dec. 2,1964, Ser. No. 423,620

1 Claim. (Cl. 29203) This application is a division of a parentapplication S.N. 299,866 filed August 5, 1963, for Printed Circuit EdgeConnector, in the name of R. J. Kinkaid et al., granted as US. PatentNo. 3,173,737 on March 16, 1965.

This invention relates generally to an improved printed circuit edgeconnector assembly of the type utilized to interconnect componentsmounted on a printed circuit card and to connect such components toindividual or paired conductive paths interconnected with the assemblyby removable tab terminals. The invention features a novel latchingassembly having a utility apart from printed circuit card use andincludes a preferred embodiment of such in a novel terminal commoningblock. The widespread acceptance and use of printed circuit cards hassponsored the development of the so-called edge type con- ,nectorwherein a plurality of contact spring members are secured within acommon insulating block member to define contact faces adapted toreceive and interconnect each path of a number of parallel conductivepaths mounted on the surface of an insulating card or panel.

v Extensions from each spring member are usually positioned in thecommon block to provide connection points for associated circuit pathsterminated thereto in some fashion. A typical construction of the priorart is shown in US. Patent No. 2,908,775 to L. Gilbert granted October13, 1959. Further examples of the prior art devices are shown in US.Patents No. 2,935,725 to B. Fox granted May 3, 1960, No. 2,870,424 to E.E. Franz granted January 20, 1959, No. 3,001,171 to F. A Shultz grantedSeptember 19, 1961, and No. 3,016,508 to G. J. Lalonde granted January9, 1962.

While the connectors of the prior art have generally answered thelimited needs for which they were designed, field experience hasoutlined new demands not met by prior art devices and has provided anassessment of major shortcomings understandably overlooked in the earlyefforts of development of edge type connectors.

A basic shortcoming has been the lack of structure to adequately provideremovable associated leads in conjunction with means for latching suchleads against accidental withdrawal. The typical approach has been toprovide either a soldering tab which is, of course, not readilyremovable or a bare conductor or taper pinreceptacle not suitable forrepeated insertion and withdrawal. A shortcoming in common with theabove approaches has been the lack of an insulating structure completelyoverlying the conductive portions of the connector. This lackpractically bars use of such connectors in any environment crowded byother electrical components and leads; the typical environment found inaircraft, ships and the like.

A further shortcoming has been the lack of a printed circuit card springmember which is readily producible and useable and which at the sametime ofiers a sufficient contact area driven by sufficient contactspring pressure. In one prior art approach, for example, the contactsurface for the printed circuit card is defined by raised indentationsin the contact spring member which reduces the total contact surface tothat of a single point or at most a few points located along theindentation width. Through this approach contact pressures are of coursemaximized but unfortunately contact surface Wear is so increased as toalmost insure removal of precious metal plating from contact surfaces aswell as damage to corresponding con- 3,251,125 Patented May 17, 1966ductive paths on printed circuit cards. Other prior art etforts haveextended the possible contact surface between card path and contactspring by the use of cantilevered arm members angled to coincide withthe plane of the printed circuit conductive path. Yet other approacheshave made use of bellows type spring members having a length sufiicientto provide a relatively long trailing portion to define the contactarea. Experience with such spring configurations has shown a tendencyfor the springs to become set following only a few insertions of aprinted circuit card and in a manner to so reduce spring force as toreduce the qualities of electrical connection below that which isadequate. Additionally, with spring members of considerable lengthproblems have been encountered in maintaining production tolerances toachieve proper positioning of contact surfaces which are well removedthrough a number of turns from the juncture of spring arm and supportingmember. This adversely affects use and reliability. A still furthershortcoming of certain prior art edge connectors has been the lack ofany facility for changing the contact springs or the associatedterminals to thus change the interconnections between card components-orreplace worn or damaged contact members. In the prior art edgeconnectors having a facility for replacing contact springs or theassociated terminals, a shortcoming has been found with respect to thecomplexity of insulating and metal parts required to mount and lock themembers within the insulating housing block. This has resulted in acomplexity of insertion-withdrawal tooling as well as in extending thetime required for such and the likelihood of contact damage due to theexcessive manipulation required. Still further shortcomings include therequired use of polarized-terminals for associated leads, thepossibility of terminal movement within the connector assembly, theprovision of contaminant entry points and over-all lack of adaptabilityto economical production and use.

Accordingly, it is an object of the invention to provide a tool for amultiple connector incorporating contact spring members mounted Within aprotective insulating housing.

It is another object of invention to provide a tool for use with animproved multiple connector featuring ter minals, terminal springmembers, an associated latch structure which permits to rapid insertionand withdrawal of the terminal members without part damage.

It is yet another object of invention to provide a tool for use with animproved multiple connector wherein the configuration of contactassembly tool and insulating housing block is such as to reducetolerance problems with respect to initial assembly and use and therebyenhance cost or reliability.

The foregoing objects are achieved by the invention through thecombination of an insulating housing block including a series ofessentially straight walled transverse cavities having a singleprojection to cooperate with and retain a series of multiple functioncontact spring members. The contact spring members are orientated toreceive on one side through a slot the conductive paths of a printedcircuit card and on the other side one or more tab terminals connectedto associated circuit leads. The

spring contact members fitted within the block are of a 1 uniqueconfiguration to both permit the use of a simple one-piece molding andyet provide a means whereby the members are locked therein againstaccidental withdrawal and relative movement. As an important aspect ofthe invention the contact members include a unique spring armconfiguration for each of four separate functions of contact andmechanical connection. Each contact spring features an embossedstiffening spine and angular disposition to minimize tolerance and setproblems and maximize contact area and pressure. The latching springfeatures a progressive stilfening action and an overtravel blockingfeature which combine to provide a reliable but simple captivation oftab terminals and preclude terminal or contact member damage bysimplifying tool requirements.

Utilizing the above advantages of contact member construction analternative embodiment is included for extending the utility of theinvention to accommodate a greater number of associated conductive leadterminals. Yet a further embodiment is included utilizing certain of theprinciples of the block and spring construction of the invention toaccomplish a commoning function for large numbers of associatedconductive leads apart from printed circuit card use. Finally, a toolembodiment of simple construction is included which permits rapidterminal withdrawal without contact damage. In the drawings:

FIGURE 1 is a sectioned perspective of one embodiment of the connectorof the invention showing the general configuration of the insulatinghousing and contact member mounting features;

FIGURE 2 is an elevational section of the connector embodiment of FIGURE1 depicting a contact member,

its engagement within the housing block and its operation in receiving aprinted circuit card;

FIGURE 3 is a section taken along lines 3-3 of the embodiment shown inFIGURE 2 further showing the cooperation of the contact member andhousing cavity;

FIGURE 4 is a perspective showing the contact member of the embodimentshown in FIGURE -2 removed from the housing to depict its latchingfeature with a preferred construction of tab terminals;

FIGURE 5 is a section taken through the width of the contact along lines55 of FIGURE 4, showing the tab terminal spring members;

FIGURES 6 and 7 are sectional views taken along the .length of thecontact member, lines 66 and 77, revspectively of FIGURE 5;

FIGURE 8 is a section taken along the length of the contact member, line8-8 of FIGURE 9, showing a tab terminal inserted within the terminalspring member of the contact member;

FIGURE 9 is an elevational view of the contact member apart from theblock including a fully inserted tab terminal and a partially insertedtab terminal to show the operation of the novel latching feature of theinvention;

FIGURE 10 is an alternative embodiment of the connector of the inventionshowing a modified housing con- .struction in section in conjunctionwith a modified contact spring member;

FIGURE 11 is an elevational section taken along lines 1111 of theconnector shown in FIGURE 10;

FIGURE 12 is an elevational section taken along lines 1212 of FIGURE 10;

FIGURE 13 is an end-on view taken from lines 13--13 of the assembly ofFIGURE 10;

FIGURE 14 is a perspective of yet a further embodiment of a contactspring of the connector of the invention adapted for use as a commoningmeans for numbers of tab terminals and associated conductive leads;

FIGURE 15 is a sectional view of the block embodiment adapted for usewith the commoning contact spring shown in FIGURE 14;

1616 of FIGURE 15;

FIGURE 17 is a perspective of an extraction tool embodiment for use witha connector of the invention; and

FIGURE 18 is an elevation showing part of the connector assembly inconjunction with the tool shown in FIGURE 17 in use.

Turning now to a detailed description of the invention, FIGURE 1 shows afragmentary length of one embodiment of the connector block member ofthe invention. This member labeled 10 is preferably a one-piece moldingof dielectric insulating material of the thermo-setting type, such, asdiallyl phthalate, epoxy, phenolic resin or the like. In an actual unit,a glass loaded diallyl phthalate resin was utilized. In practice, blockmembers 10 are made up to accommodate standardized printed circuit cardsizes and numbers of conductive paths such as for example, cards havingelevent pairs of conductive paths located on the surfaces of the card.It is the usual practice to provide at the ends of block member 10, notshown, mounting flanges apertured to receive members for fastening theblock through a suitable opening in a connector panel.

As can be visualized from FIGURE 1, the greater length of block member10 is along a diagonal axis extending to the right of the figure. Alonga side 12, of 10, is a centrally located slot 14 sized to accommodatethe insertion of printed circuit cards therein. Bordering slot 14 arebeveled portions 15 and 16 which serve the dual purpose of easinginsertion of printed circuit cards and eliminating the most frequentpoint of block breakage.

The opposite edge of block 10 includes a series of rectangular-apertures18, individually defining entry to a series of cavities 20 which extendacross the width of the block to join slot 14. As can be seen fromFIGURE 1, each cavity 20 has a relatively simple interior configurationto thus permit block 10 to be molded in one piece. The relativesimplicity of the construction of block 10 compares favorably to theconstructions of prior art devices which include numbers of interiorlyformed slots, projections and grooves and in certin instances anchoringapertures in the top and botton walls of the block members. The blockmember 10, as shown, includes only apertures at the points of entry ofconductive paths. The provision of a block having no apertures in thetop or bottom walls improves overall connector operation by reducingaccess for dust, moisture and the like which may contaminate contactsurfaces within the connector assembly.

Viewing FIGURE 1 further and additionally FIGURES 2 and 3, cavity 20 isseen to have bottom and top walls 22 and 24 and a side wall 26 which arestraight and free of offsets, projections and the like. The end wall 28partially closing one end of cavity 20 is also of a relatively simpleconfiguration. The side wall 30 which is the other side of the wall 26of an adjacent cavity has essentially a planar surface configurationwith a single raised projection 32 extending along a portion of itslength with one end near aperture 18. Projection 32 includes a slightlyrounded end portion 34 and an opposite abrupt face 36 which serve tolock a spring contact member within cavity 20 ina manner to behereinafter described. 2

Wall 30 further includes at the other end a slot 38 aligned with slot14. The portions 42 and 44 of wall 30 defining slot 38 are spaced apartby the width of slot 14 to accommodate insertion of a printed circuitboard as shown in FIGURE 2.

Vertical face 40 of slot 38 is positioned with respect to slot length toserve as a stop to control the depth of insertion of printed circuitboards Within the connector. The portions 42 and 44, respectively formedin wall 30 serve to provide printed circuit card support and electricaland mechanical isolation between spring arms of individual springcontacts within each cavity 24. Located between the walls 26 and 30 areV grooves such as 48 shown extending out into bevel 15 in the lower partof wall 12.. A similar V groove 46 is positioned in the upper walls 12for each cavity 20. The purpose of grooves 46 and 48 is to providekey-ways to cooperate with keying projections of the printed circuitboard;

It will, of course, be appreciated that each of the cavities 20 are asdescribed and others would be provided adjacent thereto. As will be mademore apparent hereinafter, the relatively straight and uncomplicatedsurfaces defining each cavity 20 serve to simplify mounting andretaining contact spring members inserted within each cavity. The use ofa single projection, such as 32, extending within each cavity 20 as willbe hereinafter shown, ad-

ditionally, simplifies the insertion procedures necessary duringassembly of the contact spring members within the connector block andwithdrawal procedures during the replacement of worn or broken parts aswell as prow'ding an important simplification of the tooling requiredforsuch procedures. All of these factors tend to make both production anduse of the novel connector of the invention more economical and added tothe over-all reliability of the connector by reducing the opportunityfor failure.

The contact spring assembly which represents the embodiment of theinvention utilized with the connector block above described is shown asmember 50 in FIG- URES 2-9., Member 50 is, of course, of conductivemetal and preferably of material having spring quality characteristics.In an actual embodiment, member 50 was formed of a single piece ofcontact grade Phosphor bronze blanked, stamped and formed into theconfiguration shown and thereafter over-plated with a layer of nickelbeneath a layer of gold.

Basically, the contact spring member 50 has four separate but relatedfunctions including, features to secure the member within cavity 20;spring arms of one configuration to connect with a printed circuit card;spring arms of another configuration adapted to connect with terminalsinserted therein and, further spring arms adapted to mechanically latchtab terminals within member 50.

As a first of these features, member 50 includes as shown in FIGURE 5 acentrally disposed wall 5-2 joined by intersecting walls 54 to define achannel 56 considerably wider and slightly deeper than similardimensions of projection 32 extending within cavity 20. Extending withinchannel 56 is a c-antilivered spring member 58 struck inwardly from wall52 to define a face 60 adapted to cooperate with face 36 of projection32 and relative to FIGURES 2 and 3, limit the leftward axial movement of50 within block 10. The width of face 60 is preferably made sufficientlylarge as to define a bearing area with face 36 so as to avoid toleranceproblems and provide a suflicient area of contact to prevent excessiveaxial loading of 50 from causing 60 to bite into or break off portionsof 32. The inward disposition of 58 is preferably suflicient to place 60well down on face 36 for the same reason. The length of 58 relative tothe thickness of the material is preferably made such as to define astiff spring action since the principal function of 58 is to lockcontact 50 within block rather than to latch such member in a manneradapted for frequent use of spring characteristics. This may be betterappreciated by considering that as a matter of practice member 50 wouldrarely be inserted, removed and reinserted since removal would only befor the purposes of replacing a worn or broken part.

As an extension of wall 52, a tapered portion 62 is provided extendinglongitudinally along the wall center line away from 58 and formedoutwardly as shown in FIGURE 3 with respect to channel 56 at an end 64to a maximum excursion at a point 66. From point 66 extension 62 curvesback inwardly through the plane of 52 to define a flange 68 having aninterior face 70 adapted to cooperate with a face on the end of34 ofprojection 32. As will be apparent from FIGURE 3, the distance betweenface 70 and face of spring 58 is substantially that of the length ofprojection 32 to resist axial movement and thus hold member 50 withinblock 10 against the forces of insertion and withdrawal of the printedhold 50 within cavity 20 between the faces of wall 26 and projection 32.As will be apparent from FIGURES 'with side walls 26 and 30. Thus, fromthe channel 56 formed by walls 54, the material of 50 extends outwardlyparallel to 52 to form a wall 74, thence upwardly parallel to walls 54to form a wall 76 and inwardly again parallel to wall 52 to form a wall78. Walls 74, 76 and 78 and similar walls 73, 77 and 79 form receptacles80 and 81 on either side of channel 56. In each wall 74 and 73, there isan embossment struck inwardly such as 75, shown in FIGURES 5 and 6, withrespect to receptacle 80. Emboss-ment extends along a substantialportion of receptacle and along a substantial width of of wall 74 andserves to strengthen the receptacle and member 60. :Its most importantfunction is however, to define a contact surface area for the engagementof a tab terminal inserted therein. 'Frorn FIGURE 5 it should beapparent that the walls 73, 74, 76, 77, 78 and 79 define an externalcross-sectional configuration of member 50 adapted to place considerablesurface area against the walls of cavity 20 to secure 50 againstrelative transverse movement.

With the general features of member 50, with respect to maintenancewithin cavity 20 now in mind, the improved printed circuit contactspring of the invention will now be described. Referring to FIGURES 2, 3and 4, a description of the upper contact spring arm will be given withthe understanding that the lower spring arm is identical in structureand function. As can be seen from FIGURE 2, the arrangement of theprinted circuit spring arms 84 and 104, is such as to define contactsurfaces extending down within the path of travel of a printed circuitboard 110 and the conductive paths 112 and 114 on the top and bottomsurfaces thereof. The relaxed position of the spring arms as shown inFIG- URES 4 and 9, is such that upon insertion of board 110, theconductive path 112 will engage and press against the upper springmember 84 and the lower path 114 will similarly work against the lowerspring member 104 and provide'interconnection to components electricallyconnected to such conductive paths. V

As will be further apparent from FIGURE 2, spring arm 84 is an integralextension from wall 76; the wall being extended outwardly to define anoverhang 86, a first arm position 88, a bend 92 and a further armportion 93 defining the contact surface areas. Arm 93 includes a section94 joining a relief or pocket 96, a section 98 and a turned up portion100. The contact surface areas for arm 84 are defined by the undersidesurfaces of sections 94 and 98.

At the juncture of arm 84 and extension 86 is a support portion 87extending outwardly from wall 74, to join 84. Support portion 87 isincluded to generally ruggedize the spring members by strengthening thesupport of the arm at the point most likely to fail. Within the centerarea of extension 86 and extending out along the substantial length ofarmportion 88 is a tapered embossment 90, shown in FIGURES 4 and 6.Embossment 90 serves to substantially stiffen not only the point ofjuncture of arm portion 88 and extension 86, but also to strengthen 88and provide improved spring characteristics. The tapered configurationof 90 along the surface of 88 toward 92 results in stiffeningactionwhich is gradually reduced per unit of spring length. Thishas beenfound to provide a greater degree of bending of the outer portions of 88which feature serves to maintain substantial contact pressure withoutpermitting the spring member 84 to assume an unwanted set; particularlyafter use with oversized printed circuit cards.

As a most important advantage of the spring arms of the invention, eacharm portion 88 includes a bow inwardly as shown in FIGURE 2. It has beenfound that the provision of even a slight inward bow greatly en- 7.hances the ability of the spring action to provide sufiicient andconstant contact pressure and at the same time act to reduce the stresswhich tends to set and even break the spring arm at its point ofsupport. The inclusion of a straight section or an outward bow of theconfiguration of the prior art has been found to concentrate the bend-.

ing moment and incident strains to the point of juncture of the arm,rather than at some point along the middle of the arm.

The bend 92, is maintained with a substantial interior radius as shownin FIGURE 2, to effectively transfer initial spring movement to a pointtoward the middle of arm portion 88. There is of course, a bendingmoment of arm 93 about bend 92, but the inclusion of a large radius bendhas been found to effectively delay such until the board issubstantially inserted. This operates as follows. Spring arm 93 carryingthe contact surfaces has a relaxed configuration as shown in FIGURE 9,such that as board 110 is inserted, the end thereof strikes the section94 first. This causes spring arm movement upwardly of the outer portionsof 88, with little or no spring movement of 93 about bend 92.

Further insertion of board 110 engages section 98 of 93 effecting aslight further upward movement, of arm portion 88 and upward movement of93 about 92, followed by a downward movement of 92 and 94 which actionoperates to bring both contact surfaces into firm contact with theprinted circuit conductive path 112. The pocket 96between the contactsurfaces serves to define a reservoir to entrap dust particles and otherloose material wiped from the contact surfaces during engagement ofboard .110. The turned up end 180 assures that no sharp edge or burrleft from the blanking or stamping operation will damage the printedcircuit card conductive path during insertion, and particularlywithdrawal of board 110.

By providing the inward bow in arm portion 88, the desired operationabove described is assured. Additionally, by having a positiverequirement of an inward how, the presence of an outward bow isabsolutely precluded, which would not be the case of the springspecifications called for a straight section at a given tolerance whichcould permit a slight outward bow. The outward bow condition isconsidered as the worse case with respect to causing spring set andincident reduction of contact surface pressure. It has been found thatthe presence of an outward bow in portion 88 will almost assure thatonly the forward section 98 will be in contact with the printed circuitcard path 112; the section 94 being raised as the spring arm portion 88bends about its juncture with extension 86.

Referring now to FIGURES 4 and 5, generally, and FIGURES 6, 7 and 8,specifically, the structure and operation of the spring contact membersadapted to accommodate tab terminals will be described. As can be seenfrom FIGURES 4 and 5, assembly 50 includes two contact spring members120 and 132, which are substantially identical in function andstructure. As can also be seen from FIGURES 4 and 5, each spring arm isan extension of a wall portion adjacent wall 54, such as 78 with respectto member 120. The member 120 includes a cantilevered arm 122, havingdisposed along a substantial portion of its length, a tapered rib 124,with the taper extending toward the free end of the arm. The end of thearm is turned upwardly as at 126 to positively preclude damage to a tabterminal by burrs or sharp edges incident to stamping and blanking. Rib124 is struck upwardly to strengthen the spring action of 122 at thepoint most likely to fail; namely the point of juncture of the arm withwall 78. Additionally, rib 124 operates to compound the spring moment ofthe spring arm by forcing the forward portion of the arm including thecontact surface 130 to initially swing upwardly about the end of thetaper prior to the arm moment about the juncture with wall 78 to forcesurface 130 against the surface of a terminal. As a further point, andas can be seen from FIGURE 8 the embossment 75 opposite arm 120 is of aheight such as to define travel for a tab terminal such as 140 along thecenter line of the receptacle and of a length such that the insertion of140 provides a spring operation wherein the rear portion of armincluding the contact surface 128, is brought to bear against thesurface area between spring and terminal. The provision of a bevelledentry portion, such as 132, in conjunction with an arrangement whereinthe tab terminal has a travel along the center line of the receptacleoperates to ease insertion procedures.

The tab terminals utilized with spring member 50 are identical withrespect to each other and engagement within receptacles 80 and 81. Thepreferred construction is shown in FIGURE 4, with respect to terminal140 to include a blade 142 of rectangular cross-section, having a bladetip 144 bevelled inwardly from all four walls. At the opposite end areprojections forming stops 146 and 147 extending outwardly beyond thewidth of the blade to define a width dimension from outer edge to outeredge approximating that of the receptacle 80 as measured from theoutside of the walls 76 and 54. The fonward and rear outer edges ofstops 146 are abrupt surfaces perpendicular to the longitudinal axis ofblade 142. The rear edges of each stop lead into a necked down extensionof the terminal, which is embossed as at 148 to provide strength at thepoint of juncture between. the blade and an integral lead connectingportion including ears 150 adapted to be crimped inwardly against theconductive strands of a stripped cable 154. The extension includes acable support barrel 152. The terminal 140 is formed of a flat stocksheet material stamped and blanked into a configuration with the ears of150 extended upwardly prior to crimping. In an actual unit the terminalwas formed of brass, bronze or the like plated with nickel overplatedwith gold. After a suitable stripping of the end insulation of theconductor 154, and insertion through 152, cars 150 are formed inwardlyas by crimping to terminate the conductor to the blade.

Turning now to the advantages of the immediately foregoing features andto a final feature of the member 50, FIGURE 9 shows the latchingoperation which serves to secure tab terminals against accidentalwithdrawal. Formed as an integral extension from 68 are two arms 162 and172, which are identical to accommodate terminals 140 and 160.Describing only 162, there is included at the point of juncture with 68,a reverse band 164 which extends inwardly toward the center axis ofmember 50 and then outwardly to include a spring section 166 having aface 167 adapted to cooperate with the rear surface of stop 147 to lock140 within receptacle 80. Proximate end face 167 there is included anoutward projection 168, as better shown in FIGURE 4, which prevents arm162 from being driven inwardly past the edge of tapered portion 62. Thisoperates to preclude 162 from being disabled by excessive bending causedby insertion and withdrawal of a terminal or through the tool blade usedfor such. The reverse bend 164 defines a point of contact 170 with theupper surfaces of projection 32 such that the spring moment of 162 ismade sufiiciently stiff to firmly latch 140 in position but yet permitrepeated deflection for changing terminals. the inclusion of the reversebend 164-t6 define a spring action from point 170 substantially reducesthe likelihood of breakage of the spring arm at the point of juncturewith 68. In operation, as the terminal is inserted within receptacle 80the edge of the stop 147 strikes the outer surface of the spring member162 and cams the spring inwardly to permit complete insertion. As theterminal homes within the receptacle and the faces thereof abutt thereceptacle faces, the width of the stop permits the spring arm to snapoutwardly against the back face of the stop to latch and snub theterminal against withdrawal.

An important feature of the terminal latching engagement of theinvention is that the terminal members may It has been found that beinserted without regard to polarization. 'I he planar blade constructionof the terminals in conjunction with stops on both sides of the bladepermits latching by 162 or 172 with the terminal oriented in either ofthe positions shown in FIGURE 4. Providing a terminal and latchconstruction such that the terminals may be inserted without regard topolarization, greatly facilitates assembly and withdrawal procedures aswell as simplifying tooling requirements. This will be more fullydescribed with respect to FIGURES 17 and 18 hereinafter.

Turning now to an alternative embodiment of the invention, FIGURES 13show a connector having a pair of tab terminals for each printed circuitcard conductive path. The alternative embodiment shown as connector 180in FIGURE 10, is comprised of an insulating housing 181 of dielectricmaterial having a rear terminal housing portion 182 and integraltherewith, a forward spring arm housing portion 184. The rear portion182 includes a pair of cavities 186 and 188, extending through the widthof 182 to join a common cavity 190 within portion 184. The outer wall of184 is provided with a slot 192 adapted to accommodate the insertion ofa printed circuit board 196, having upper and lower paths 198 and 200,respectively. Surrounding slot 192 is a bevelled portion such as lowerpart 1% similar in function to the bevels and 16, above described.Within cavity 190 are wall portions 202 and 204 extending inwardly todefine a bearing surface for printed circuit board 196 and to isolateand insulate the contact spring members from adjacent contact members.

Located within each cavity is a projection similar to the projection 32described with respect to the embodiment of FIGURE 1. As can be seenfrom FIGURE 11 with respect to the pair of cavities, 186 and 188, theprojections 206 and 288 respectively extend from relative opposite wallsof the cavities. This permits the use of an identical spring contactmember for each cavity. Dividing cavities 186 and 188, is a common wallportion 210 extending along the length of 182 to-define opposite slot192 a bearing surface 212 as shown in FIGURE 10 adapted to receive andblock inward movement of the spring arms of the contact member-s.Through the provision of the end 212, the spring arms are positivelypre- I vented from contacting each other to cause an electrical shortbetween the circuit path in the upper part of the assembly and thepathin the lower part. A vertical face 214 is provided at the end of 210 toact as a stop against which the end of printed circuit board 196 willoperate.

Provided in the outside portion of each cavity is an offset such as 216to define a face 218 adapted to serve as a locking surface to preventwithdrawal of a contact member from the cavity. Further includedadjacent offset 216 is an aperture 220, adapted to receive a tool bladeutilized to withdraw a contact member from the cavity. Cavity 188, ofcourse, includes portions similar to 216, 218 and 220, as shown inFIGURE 10. A face 222 is provided extending up from each cavityprojection to act as a stop against which each contact spring member isheld against axial movement developed by withdrawal of a printed circuitboard. Further included within each cavity and as better shown in FIGURE13, is a projection 224 extending along the cavity centerline to join araised ledge 226 which cooperates with the opposite wall of a cavity tosupport the latching portion of the spring member within the cavity. Ascan be seen from FIGURE 10, the connector block, 181 is of a construction which may be manufactured in a one-piece molding to assureintegrity of the unit. Note also that there are no apertures on the topand bottom walls of the block section 182 to provide access for dust orother contact surface contaminants.

Within each cavity is an identical contact membersuch as 230 shownwithin cavity 186. The spring members include, referencing now FIGURES10 and 11, a central wall 232 joined by side walls 234 to define achannel member 236 adapted to cooperate with center projection 206 tokey insertion of the contact member and support such against transversemovement relative to the housing. From the ends of walls 234 extendwalls 238, 240 and 246, to define on one side, a terminal receptacle 250and a similar structure on the other side to define a terminalreceptacle 252. The wall spacing is such as to define bearing surfaceswith the appropriate cavity walls. The upper wall 249 shown in FIGURE 10includes an extension having a reversely struck out spring member 254relative to the material thickness, which is such as to define arelatively stiff spring action to lock rather than latch assembly 230within the cavity 186.

As an extension of wall 232, there is provided as shown in FIGURE 13 analternative latching construction consisting of a wall 260, having atits end a formed U- shaped portion 262 with each wall of the U includinga spring member extending back toward the printed circuit spring arm ofthe contact member. Each spring member 264 and 266 as shown in FIGURE 10is formed inwardly such that the members are in light contact and thenbow outwardly to define end faces such as 268, adapted to engage thestop of tab terminals inserted within the contact member 239. One suchterminal mem her is shown engaged in the upper part of cavity 186. Thelatching embodiment shown in FIGURE 10 has the advantage of occupyingless width than the embodiment shown and described relative to FIGURE 9.It has been found that the provision of the spring arms 264 and 266contacting each other through an inwardly bowed portion operates withsimilar advantages to those of the embodiment above described; namelythat a relatively stiff but workable spring action is defined withunwanted set or breakage at the point of juncture of the spring arm andits support 262 eliminated. The member 230 is adapted to receive tabterminals such as 270 in one or both of the receptacles 250 and 252 tocontact terminal spring arms 272 and 274, respectively. Arms 272 and 274are identical in structure and function to arms and 132 described withrespect to FIGURES 4-8.

The printed circuit spring arms, shown in FIGURE 10 as 230, areessentially the same as the spring arms defined with respect to FIGURE2, except that only a single spring arm is provided for each contactmember 230 and the arm is oriented outwardly rather than inwardly.Additionally, the arm end 282, is for-med as indicated to engage theforward portion 214 to prevent contact with the opposing spring arm ofan adjacent member 230.

With the embodiment shown in FIGURES 10l3 and only a slightly morecomplicated housing block plus a pair of identical spring members, theutility of the invention is considerably extended with respect to thenumber of circuit paths accommodated. The principal advan-,

tages theretofore described with respect to the embodiment of FIGURE 2are carried forth in the embodiment shown in FIGURE 10. In both of theabove embodiments, as well as in the following commoning blockembodiment, all conductive material isdisposed well within a protectiveoverhang of dielectric material. In all embodiments the principal facesdefining "the latching of terminals are metal rather than one face metaland an opposing face dielectric.

Turning now to yet a further embodiment of the invention, FIGURES 14, 15and 16, show a connector commoning block adapted to accommodate numbersof terminal paths apart from any use with a printed circuit card. InFIGURE 14, a contact spring assembly 300 is shown to include a one-piecemetal stamping with identical individual spring members 301 joined by anintegral bus formed of bars 310 and 314. The composite assemblyincluding numbers of members 30, is adapted to be fitted within a commoninsulating housing 330 shown in FIGURES 15 and 16.

As can be seen in FIGURE 14, each member 300', is comprised of a bodyportion 302 having a central forward extension 303, including lockingspring 304 and a latching spring assembly 305, which is essentiallyidentical in function and arrangementto the locking and latchingstructure shown in FIGURES 2, 4 and 8. Extending along each side of 303are walled channels, such as 306, each defining a receptacle similar infunction to the receptacles 80 and 81, described with respect to FIGURE5. Positioned within the receptacle formed by channel 306 is a terminalspring member 307 which is identical in structure and similar infunction to the spring member 120 described with respect to FIGURE 4.The operation of each spring member such as 307, with respect to thecontact of a tab terminal, is reversed from that shown in FIGURES 6, 7and 8, in that the insertion is from the opposite end of the spring asindicated in FIGURE 14 by the dotted line, with respect to tab terminal308. The channel 306, includes in its lower wall, an embossment similarto that shown in FIGURES 6, 7 and 8, to define an axis of insertionalong the geometrical center of the channel in the same manner as shownin FIGURE 8. With the blade of the tab terminal 308, fully insertedwithin channel 306, the contact innerface between the tab blade and thespring member and lower embossment is essentially as shown in FIGURE 8,with'the blade, of course, relatively oppositely oriented. The latchingfeature is as shown in FIGURE 9, with the latching stop 309 engagedunder the adjacent spring member of assembly Formed from assembly 300,and extending out of the channels defining tab receptacles are integralbus members 310 and 314. The forward bus member 310 includes a bevelledand downwardly formed portion 312 to permit clearance at the point ofinsertion of the tab terminal and thus avoid any possibility ofinterference with terminal insertion. The rearportion of 302 includes atransverse wall 316 relieved as at 318 to cooperate with the interiorsurfaces of a complementary cavity in an insulating block housing.

The housing shown as 330' in FIGURES 15 and 16 is a one-piece molding ofthermosetting material such as glassfilled diallyl phthalate comprisedof the side walls 334 and 336 connected by a common back wall 335 andincluding a dividing wall 340. The housing 330 is, through suchconstruction, capable of accommodating two assemblies 300 having memberssuch as 301; it of course, being understood that the housing could bemade in one half as along the dotted line of FIGURE 15 to accommodate asingle strip of contact member. Extending inwardly from each outer wall332 and 336, are projections such as 334 and 338, which have a length todefine faces 335 and 337 spaced to receive the inner face of eachassembly 305 and a contact spring 304 to lock the contact member andstrip within the housing. The operation of each projection is identicalto projection 32 described with respect to FIGURE 2. Projections 344from wall 340 are included to provide support for each contact member.

As can be seen from FIGURES 15 and 16, each contact member or strip ofcontact members is inserted within the insulating block with theprojections 344 fitted within the-space between adjacent spring members301 and with the projections 334 fitted within the relief 318 down alongmember 303 to engage the contact spring 304 and the end of assembly 305to lock the assemblies within the block.

With assemblies of the type shown in FIGURES 14, 15 and 16, commonedinterconnections are provided between conductive leads attached to tabterminals inserted in any contact assembly.

As one of the advantages of the invention, attributable to the novellatching arrangement, the tooling required for insertion and withdrawalis greatly simplified. From the general description above given,- itwill be apparent that no special tool is required to insert the tabterminals within the assembly. The conductive lead portion adjacent atab terminal may be gripped and the terminal inserted in the appropriateaperture until the terminal stop is engaged and latched by the springmember. Due to the arrangement of parts, this insertion procedure may bedone blindly without regard to polarization and with regard only to theorientation of the blade with repect to the slot; and orientation whichis identical to aperture length.

FIGURE 17 shows a tool prepared for use in withdrawing tab terminalsfrom the connector assemblies heretofore described. The tool 350 iscomprised of a metal channel U-shaped along a substantial portion of itslength and including at one end, a pair of tynes 352 and 354. The tyne352 is as shown in FIGURE 18, approximately twice the length of tyne354, as measured from the body of the tool, and each is slightly less inwidth than an aperture such as 18 in FIGURE 1. Both tynes are relativelyshort as compared with prior art devices and for this reason toolbreakage is substantially minimized and tool manipulation is simplified.As can be seen, the tool construction is quite simple although notfragile. In an actual embodiment, the tool was formed of spring steelsheet stock blanked to a fiat configuration and folded into the channelshape and thereafter spring tempered and given a protective coating ofgun metal bluing. If desired, a handle as shown by the dotted line inFIGURE 17, may be provided on the end of the tool opposite to tynes 352and 354, although such is not necessary for its use.

FIGURE 18 shows the operation of the tool in a preferred manner toextract a tab terminal. In such use one terminal at a time is extractedby positioning the tool as shown in FIGURE 18, with the longer tyne 352inserted in a block aperture against the terminal to be withdrawn. Theadjacent terminal may be extracted by merely reversing the tool andprocedure indicated in FIGURE 18. During the extraction, the preferredmanner for use of the tool is to grip the tool between the thumb andforefinger and firmly insert 352 fully inwardly to butt against the stopof the terminal; against 364 of 362. In this position, the spring membersuch as 366 of the contact member will be depressed. Then, withforefinger pressing the lead against the tool the terminal and lead canbe then withdrawn, the bottom portion of the tyne acting to permitwithdrawal of the terminal past the end face of the latching spring. Asa part of the novel construction of tool 350, the lower tyne 354 servesto prevent misorientation of the tool such that 352 could be twisted todamage the latching spring member. The spacing between 352 and 354 issuch as to place 354 lightly against the lower portion of the latchingspring as the tool is fully inserted. The latching assembly and toolarrangement is such as to avoid stressing the contacts of the printedcircuit board at any time during the above procedure.

In order to fully develop a preferred form of the invention, theforegoing description has been in considerable detail and should enableone skilled in the art to readily practice the various embodimentsfollowing the specification and drawings of the case. As will beappreciated by those skilled in the art, certain aspects of theinvention may readily be directly employed to provide features identicalin function and equivalent in structure. For example, with respect tothe latching feature of the invention, the specification has detailed areceptacle and tab terminal configuration wherein the terminal isrectangular in cross-section and includes a blade contact surface. Theconcept of providing a latching spring which latches metal to metalrather than metal to a plastic part of a housing and includes a snubbingaction may be adapted to receptacle and terminal configurations otherthan that shown. For example, the terminal blade could be of acylindrical-or even tapered shape such as a solid pin, with acomplementing receptacle having interior surfaces such as to receive thepin and further including at the base of the pin, a rim operating as thestop of the device. In such event the block housing cavities would be ofa configuration such as to receive the alternative receptacleconfiguration.

In each of the embodiments above given a dual assembly has been showncapable of accommodating a pair of terminals. It is fully contemplatedthat half of the structure shown-could be'utilized to accommodate andlatch a single terminal per contact spring assembly. As modified, thisunit could be utilized with the commoning block embodiment or couldinclude a single printed circuit contact spring of the configurationshown. In shown case the insulating block would merely be modified tosupport the assembly in a manner similar to that shown.

It has also been found useful to practice the invention in a formwherein there is a single cavity within an'insulating block including asingle contact spring member of the type shown in FIGURE 2 as a testprobe to printed circuit board devices or as a commoning path from aboard upper conductive path to a board lower conductive path through acommon conductive lead having the terminals at each end inserted in thereceptacles of the spring member.

Changes in construction will occur to those skilled in the art andvarious apparently different modifications and embodiments may be madewithout departing from the scope of the invention. The matter set forthin the foregoing description and accompanying drawings is offered by wayof illustration only. The actual scope of the invention is intended tobe defined in the following claim when viewed in their properperspective against the prior art.

We claim:

In a tool for use in pulling terminals from the rear slots of aconnector block of the type containing contact structures each includinga pair of terminal receptacles in parallel relationship separated by acommon projection carrying a pair of latches extending inwardly of saidblock and obliquely of the associated receptacle to latch terminals inassociated leads in said structure the improvement comprising aone-piece metallic stamping of thin flat stock having a U-shaped bodyportion, a pair of parallel tines on one end of said body portionprojecting axially.

therefrom, the said tines being spaced apart by a distance to fit overthe said common projection and engage said latches, one of said tinesbeing sufliciently longer than the other of said tines to deflect onelatch inwardly before the other tine deflects its associated latch uponinsertion of said tool within said block, the other tine serving to holdsaid tool in alignment by engagement with said latch during manipulationof said tool, the said tool further including a portion behind saidtines to permit the lead of the terminal associated with a deflectedlatch to be held thereagainst to permit the said terminal and lendof'the deflected latch to be pulled from said block.

References Cited by the Examiner UNITED STATES PATENTS 2,252,816 8/ 1941Santrey 29-27 8 X 2,63 8,025 5/ 1953 Nelson 29-270 2,978,800 4/1961tBlain 29-203 3,087,235 4/ 1963 Porter 29-206 3,168,750 2/ 1965 Gattiker29-203 WHITMQRE A. WILTZ, Primary Examiner. THOMAS H. EAGER, Examiner.

